Process for avoiding the overcharging of drives for rayon centrifuges



E. KNECHTEL 2,107,758

PROCESS FOR AVOIDING THE OVERCHARGING OF DRIVES FOR RAYON CENTRIFUGESFeb. 8, 1938.

Filed March 4, 1931 Patented Feb. 8, 1938 PATENT OFFICE PROCESS FORAVOIDING THE OVERCHARG- ING OF DRIVES FOR RAYON FUGES CENTRI- ErichKnechtel, Sydowsaue, near Stettin, Germany, assignor to North AmericanRayon Corporation, a. corporation of Delaware Application March 4, 1931,Serial No. 520,162 In Germany March 10, 1930 Claims.

7 g In the manufacture of rayon, especially viscose This is particularlythe case if the spindle speed exceeds 5,000, for instance at from 7,000to 12,000 revolutions per minute,where it has been found that in acontinuous. operation during which, in the course of several hours, thespinning pot is gradually filled with fresh rayon, the'necessary drivingforces increase in an incomprehensible 15 manner which, especially inthe case of electric ,motors, may cause dangerous over-loadings. It hasbeen found that this increase and additional load during such a spinningperiod is hardly caused-by an increased friction of the gears, or by thelarger amount of rayon in the spinning pot. A more thoroughinvestigation shows that with this large number of revolutions asrequired by the high spinning speed, and more so with the manufacture ofa strong warpv twist, crystals are caused by the evaporation of spinningbath solutions out of the spinning pot. The evaporation is acceleratedby the great surface speed of the pot in the surrounding atmosphere.Further tests have shown that these salt crusts make the surface of thepot uneven and thus cause a larger amount'of friction in the air, whichagain causes theabove over-load.

According to the present invention the formation of these salt crusts iseliminated, or the 35 deposits are continuously or intermittently re- 7moved. This may be done in different ways.

Thus, the spinning pots can be sprayed continuously or intermittentlywith liquids, such as warm water, during the working time. This water 40is able to dissolve the salt crusts immediately after they begin toform. Another method of procedure is to maintain such atmosphericconditions in the spinning pot chambers as will not allow the formationof salt 45 crusts, e. g. by maintaining an especially high air 50 likeform in tangential direction on the outer mantle of the centrifuge potin the direction of I its rotation. I In the drawing accompanying thisapplication, Figure 1 is a cross sectional view through the chamber of aspinning centrifuge illustrating the use of my invention.

Fig. 2 is a plan view of a plurality of spinning chambers illustratingthe use of my invention with the covers of said chambers removed.

In the drawing in which like numerals of reference indicate like parts,I represents the vertical walls of the spinning chambers and 2 indicatesthe bottom partition.

The partition 2 has an opening 3 through which the spinning spindle 4projects. The spinning pot 5 is supported and rotated by the spindle 4.A cover 6 having an opening 1 for the insertion of a thread guide tube(not shown) is illustrated in Figure 1.

In order to eliminate the formation of the aforementioned salt crustswith consequent danger of overloading the rotating means, the pots aresprayed during rotation with liquid which is brought through thespinning chamber by means H of a supply pipe 8. Branch pipes 9 havingnozzles in are supported on the supply pipe 8 and are positioned in sucha manner as to send a fan shaped spray tangentially against the side ofthe spinning pot. This eliminates the formation of crystals with theresultant danger to the spinning operation.

From the foregoing description taken in connection with the accompanyingdrawing, it is believed that the operation and advantages of myinvention will be apparent. to those skilled in the art.

Having now fully set forth my invention as required by the patentstatutes, what I desire to claim is:

1. In the method of collecting wet spun filaments in a driven spinningpot, the step of submitting the outer surface of the pot to a spray ofliquid in a direction tangential to the said surface and in thedirection of rotation thereof while the centrifuge is in operation.

2. In the method of collecting spun filaments in a driven spinning pot,the step of submitting the outer surface of the pot to a fan-shapedspray of liquid in a direction tangential to the said surface and in thedirection of rotation thereof while the centrifuge is in operation.

3. In the method of collecting spun filaments in a driven spinning pot,the step of submitting the outer surface of the pot to a periodic sprayof liquid in a direction tangential to the said surface and in thedirection of rotation thereof while the centrifuge is in operation.

4. In the method of collecting spun filaments in a driven spinning pot,the step of submitting the outer surface of the pot to a spray of liquidin a direction tangential to the said surface and. in the direction ofrotation thereof while the centrifuge is in operation the said spraybeing discontinued during a part of the operation of the 5 centrifuge. 1

ERICH KNEC I-ITEL.

